referrer_charset is a lie. It's really the user's default_charset.

net/http/http_content_disposition_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/http/http_content_disposition.h"
 
 #include "base/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace net {
 
 namespace {
 
 struct FileNameCDCase {
   const char* header;
-  const char* referrer_charset;
+  const char* default_charset;
   const wchar_t* expected;
 };
 
 }  // anonymous namespace
 
 TEST(HttpContentDispositionTest, Filename) {
   const FileNameCDCase tests[] = {
     // Test various forms of C-D header fields emitted by web servers.
     {"inline; filename=\"abcde.pdf\"", "", L"abcde.pdf"},
     {"inline; name=\"abcde.pdf\"", "", L"abcde.pdf"},
@@ skipping 36 matching lines @@
     {"inline; filename=\"=?iso88591?Q?caf=E9_?= .png\"",
      "", L"caf\x00e9 .png"},
     // Two encoded words with different charsets (not very likely to be emitted
     // by web servers in the wild). Spaces between them are removed.
     {"inline; filename=\"=?euc-kr?b?v7m8+iAz?="
      " =?ksc5601?q?=BF=B9=BC=FA=2Epng?=\"", "",
      L"\xc608\xc220 3\xc608\xc220.png"},
     {"attachment; filename=\"=?windows-1252?Q?caf=E9?="
      "  =?iso-8859-7?b?4eI=?= .png\"", "", L"caf\x00e9\x03b1\x03b2.png"},
     // Non-ASCII string is passed through and treated as UTF-8 as long as
-    // it's valid as UTF-8 and regardless of |referrer_charset|.
+    // it's valid as UTF-8 and regardless of |default_charset|.
     {"attachment; filename=caf\xc3\xa9.png",
      "iso-8859-1", L"caf\x00e9.png"},
     {"attachment; filename=caf\xc3\xa9.png",
      "", L"caf\x00e9.png"},
     // Non-ASCII/Non-UTF-8 string. Fall back to the referrer charset.
     {"attachment; filename=caf\xe5.png",
      "windows-1253", L"caf\x03b5.png"},
 #if 0
     // Non-ASCII/Non-UTF-8 string. Fall back to the native codepage.
     // TODO(jungshik): We need to set the OS default codepage
@@ skipping 100 matching lines @@
     {"attachment; filename=\"foo-ae.html\"; "
       "filename*=UTF-8''foo-%c3%a4.html", "", L"foo-\xe4.html"},
     // attfnboth2
     {"attachment; filename*=UTF-8''foo-%c3%a4.html; "
       "filename=\"foo-ae.html\"", "", L"foo-\xe4.html"},
     // attnewandfn
     {"attachment; foobar=x; filename=\"foo.html\"", "",
       L"foo.html"},
   };
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(tests); ++i) {
-    HttpContentDisposition header(tests[i].header, tests[i].referrer_charset);
+    HttpContentDisposition header(tests[i].header, tests[i].default_charset);
     EXPECT_EQ(tests[i].expected,
         UTF8ToWide(header.filename()))
         << "Failed on input: " << tests[i].header;
   }
 }
 
 // Test cases from http://greenbytes.de/tech/tc2231/
 TEST(HttpContentDispositionTest, tc2231) {
   const struct FileNameCDCase {
     const char* header;
@@ skipping 296 matching lines @@
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(tests); ++i) {
     HttpContentDisposition header(tests[i].header, std::string());
     EXPECT_EQ(tests[i].expected_type, header.type())
         << "Failed on input: " << tests[i].header;
     EXPECT_EQ(tests[i].expected_filename, UTF8ToWide(header.filename()))
         << "Failed on input: " << tests[i].header;
   }
 }
 
 }  // namespace net